@Scatterbrain Nikki,
I like the newspaper idea. Unfortunately in the days of the internet and living out in the country where they won't deliver a paper off the highway makes newspapers almost a thing of the past. A small weekly local paper - and expensive - that comes via mail is about all the paper that shows up here. I think I may stack up a few and try them, though. It certainly gets wet easily enough so it seems like it would keep the water running straight through. I have paper sacks that cattle feed comes in that I may try. It's cheap paper that also soaks up water easily. I use it under mulch to suppress weed growth for that reason. I wonder if cardboard boxes would work? They also tend to be absorbent and might even be easier to stuff in the containers to fill in the shrinkage. Both those decompose rapidly when I use them outside on the soil. Not sure how fast they would disappear in the containers. Worth trying. Thanks for the idea!